City University London

About: City University London is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Health care. The organization has 5735 authors who have published 17285 publications receiving 453290 citations.

Validation of the Profile of Female Sexual Function (PFSF) in surgically and naturally menopausal women

Abstract: The Profile of Female Sexual Function (PFSF) is a patient-based instrument for the measuring of loss of sexual function in menopausal women with low libido (hypoactive female sexual desire disorder). The instrument, which contains 37 items in seven domains (sexual desire, arousal, orgasm, sexual pleasure, sexual concerns, sexual responsiveness, and sexual self-image) and a single-item measure of overall satisfaction with sexuality, has been extensively developed and initially validated in over 500 oophorectomized women with low libido in North America, Europe, and Australia. Initial validation results showed the PFSF is capable of discriminating these patients from age-matched controls and produced consistent responses and sensitivity across geographies. The objective of this nonrandomized, parallel-group study was to examine the psychometric properties of the final PFSF in an independent group of surgically menopausal women with low libido and to extend validation to naturally menopausal women with low libido. Participants from 16 study centers in North America included surgically (n = 59) and naturally (n = 88) menopausal women with low libido and their age-matched control subjects, both premenopausal (n = 57) and naturally menopausal (n = 47), who reported no problems with libido. Subjects completed the PFSF at baseline and again 4 weeks later. Adjusted mean scores for each of the seven domains were statistically significantly lower (P < 0.0001) in surgically menopausal women with low libido compared with age-matched control women, and in naturally menopausal women with low libido compared with naturally menopausal control women, demonstrating excellent discriminant validity. Test-retest reliability ranged from 0.57 to 0.91 for the seven domain scores, whereas internal-consistency reliability ranged from 0.74 to 0.95. Results of this research support the conclusion that the PFSF is a valid and reliable instrument for measurement of loss of sexual function in both naturally and surgically menopausal women with low libido.

Tight-binding theory of tunneling giant magnetoresistance

Abstract: A unified theory of the tunneling magnetoresistance (TMR) and of the ballistic-current perpendicular-to-plane giant magnetoresistance (CPP GMR) is developed. It is based on the Kubo-Landauer formula and fully realistic tight-binding bands fitted to an ab initio band structure. The theory is first applied to a single-orbital tight-binding model to investigate analytically a continuous transition from the CPP GMR of a metallic system to the TMR of a tunneling junction. The transition takes place when either hopping of electrons between the ferromagnetic electrodes is gradually turned off or the on-site potentials in the nonmagnetic spacer are varied so that the Fermi level in the spacer moves into the band gap. It is shown that the TMR approaches rapidly the same saturation value when either the interelectrode hopping decreases or the height of the insulating barrier increases. When the insulating barrier is high (band gap is large), the TMR depends only weakly on the thickness of the insulating layer. However, when the band gap is small compared to the conduction band width, the TMR decreases rapidly with increasing thickness of the insulator. The numerical results for a Co(001) junction, based on a fully realistic band structure of the Co electrodes, show a very similar behavior. As the tight-binding hopping matrix between the Co electrodes is gradually turned off, the TMR ratio drops initially very rapidly from its value of 280% in the metallic regime to about 40% but then stabilizes in the range 40--65%. This is in a very good agreement with the observed value of 40%. The polarization of the current flowing across the Co junction in the metallic regime is negative (antiparallel to the magnetization) but becomes positive in the tunneling regime. The sign of the calculated polarization is, therefore, in agreement with the sign observed in all the experiments on tunneling from transition-metal ferromagnets.

Internal and External Corporate Governance: An Interface between an Organization and its Environment

Abstract: Most corporate governance research focuses on a universal link between corporate governance practices (e.g. shareholder activism, board independence) and performance outcomes, but neglects how interdependences between the organization and diverse environments lead to variations in the effectiveness of different corporate governance practices. This paper develops an organizational approach to corporate governance and focuses on two dominant streams that analyse internal and external governance mechanisms. First, we explore governance practices aimed at dealing with a complex set of problems internal to an organization, such as conflicts of interest between managers and shareholders, different types of shareholders, and block-holder opportunism. Second, we discuss the importance of formal and informal governance arrangements that organizations use in managing their relationships with external parties, such as alliance partners, overseas subsidiaries and network members. We argue that an integrated approach bringing these two streams together helps to develop a more holistic view on the effectiveness and efficiency of various corporate governance mechanisms, and suggests a number of avenues for future research. This paper also sets the scene for this thematic issue on corporate governance, scopes the field and introduces 11 papers which make significant contributions towards our understanding of corporate governance.